Adsorption of omeprazole on biobased adsorbents doped with Si/Mg: kinetic, equilibrium, and thermodynamic studies

This paper proposes an easy and sustainable method to prepare high-sorption capacity biobased adsorbents from wood waste. A biomass wood waste (spruce bark) was employed to fabricate a composite doped with Si and Mg and applied to adsorb an emerging contaminant (Omeprezole) from aqueous solutions, as well as synthetic effluents loaded with several emerging contaminants. The effects of Si and Mg doping on the biobased material’s physicochemical properties and adsorptive performance were evaluated. Si and Mg did not influence the specific surface area values but impacted the presence of the higher number of mesopores. The kinetic and equilibrium data presented the best fitness by the Avrami Fractional order (AFO) and Liu isotherm models, respectively. The values of Qmax ranged from 72.70 to 110.2 mg g−1 (BP) and from 107.6 to 249.0 mg g−1 (BTM). The kinetic was faster for Si/Mg-doped carbon adsorbent, possibly due to different chemical features provoked by the doping process. The thermodynamic data showed that the adsorption of OME on biobased adsorbents was spontaneous and favorable at four studied temperatures (283, 293, 298, 303, 308, 313, and 318 K), with the magnitude of the adsorption correspondent to a physical adsorption process (ΔH° −1). The adsorbents were applied to treat synthetic hospital effluents and exhibited a high percentage of removal (up to 62%). The results of this work show that the composite between spruce bark biomass and Si/Mg was an efficient adsorbent for OME removal. Therefore, this study can help open new strategies for developing sustainable and effective adsorbents to tackle water pollution

Use of biochar prepared from the açaí seed as adsorbent for the uptake of catechol from synthetic effluents

This work proposes a facile methodology for producing porous biochar material (ABC) from açaí kernel residue, produced by chemical impregnation with ZnCl2 (1:1) and pyrolysis at 650.0 °C. The characterization was achieved using several techniques, and the biochar material was employed as an adsorbent to remove catechol. The results show that ABC carbon has hydrophilic properties. The specific surface area and total pore volume are 1315 m2·g−1 and 0.7038 cm3·g−1, respectively. FTIR revealed the presence of oxygenated groups, which can influence catechol adsorption. The TGA/DTG indicated that the sample is thermally stable even at 580 °C. Adsorption studies showed that equilibrium was achieved i

Removal of captopril pharmaceutical from synthetic pharmaceutical-industry wastewaters:Use of activated carbon derived from Butia catarinensis

A high surface area activated carbon was produced from the seed of Butia catarinensis (Bc), which was utilized for removing captopril from synthetic pharmaceutical industry wastewaters. The activated carbon was made by mixing ZnCl2 and Bc at a proportion of 1:1 and pyrolyzed at 600° (ABc-600). The material was characterized by the Boehm titration, hydrophilic/ hydrophobic ratio, elemental analysis, TGA, FTIR, and N2 isotherm (surface area (SBET), total pore volume (TPV), and pore size distribution (PSD)). The characterization data showed that the adsorbent displayed a hydrophilic surface due to the presence of several polar groups. The carbon material presented a TPV of 0.392 cm3 g−1, and SBET of 1267 m2 g−1. The equilibrium and kinetics data were suitably fitted to Liu isotherm and Avrami-fractional-order. The employment of the ABc-600 in the treatment of synthetic pharmaceutical industry wastewater exhibited high effectiveness in their removals (up to 99.0 %)

Adsorption of Omeprazole on Biobased Adsorbents Doped with Si/Mg: Kinetic, Equilibrium, and Thermodynamic Studies

This paper proposes an easy and sustainable method to prepare high-sorption capacity biobased adsorbents from wood waste. A biomass wood waste (spruce bark) was employed to fabricate a composite doped with Si and Mg and applied to adsorb an emerging contaminant (Omeprezole) from aqueous solutions, as well as synthetic effluents loaded with several emerging contaminants. The effects of Si and Mg doping on the biobased material’s physicochemical properties and adsorptive performance were evaluated. Si and Mg did not influence the specific surface area values but impacted the presence of the higher number of mesopores. The kinetic and equilibrium data presented the best fitness by the Avrami Fractional order (AFO) and Liu isotherm models, respectively. The values of Qmax ranged from 72.70 to 110.2 mg g−1 (BP) and from 107.6 to 249.0 mg g−1 (BTM). The kinetic was faster for Si/Mg-doped carbon adsorbent, possibly due to different chemical features provoked by the doping process. The thermodynamic data showed that the adsorption of OME on biobased adsorbents was spontaneous and favorable at four studied temperatures (283, 293, 298, 303, 308, 313, and 318 K), with the magnitude of the adsorption correspondent to a physical adsorption process (ΔH° −1). The adsorbents were applied to treat synthetic hospital effluents and exhibited a high percentage of removal (up to 62%). The results of this work show that the composite between spruce bark biomass and Si/Mg was an efficient adsorbent for OME removal. Therefore, this study can help open new strategies for developing sustainable and effective adsorbents to tackle water pollution

Biosorption of Neodymium (Nd) from Aqueous Solutions Using Spirulina platensis sp. Strains

Rare earth elements such as neodymium (Nd) are important elements used mainly in developing new technologies. Although they are found in low concentrations in nature, they can be obtained by extracting solid samples such as phosphogypsum. Among the techniques, adsorption has been used successfully with several adsorbent materials. In this work, two strains of Spirulina platensis (LEB-18 and LEB-52) were employed as biosorbents for efficiently removing the Nd element from the aqueous media. Biosorption tests were carried out in a batch system, and the results of the biosorption kinetics showed that for both materials, the biosorption of Nd was better described by the Avrami model. Moreover, it could be considered that 80 min would be necessary to attain the equilibrium of Nd(III) using both biosorbents. The result of the biosorption isotherms showed that for both strains, the best-fitted model was the Liu model, having a maximum biosorption capacity of 72.5 mg g−1 for LEB-18 and 48.2 mg g−1 for LEB-52 at a temperature of 298 K. Thermodynamics of adsorption showed that for both LEB-18 and LEB-52 the process was favorable (∆G° < 0) and exothermic (∆H° −23.2 for LEB-18 and ∆H° −19.9 for LEB-52). Finally, both strains were suitable to uptake Nd, and the better result of LEB-18 could be attributed to the high amount of P and S groups in this biomass. Based on the results, a mechanism of electrostatic attraction of Nd3+ and phosphate and sulfate groups of both strains of Spirulina platensis was proposed

Preparation of highly porous nitrogen-doped biochar derived from birch tree wastes with superior dye removal performance

Abstract Heteroatom doping is a highly effective strategy that can be used to modify carbonaceous adsorbents to improve their chemical reactivity and increase their adsorptive properties. Herein, a simple method is reported for the preparation of nitrogen-doped biochar using a natural and abundant biowaste from birch trees and melamine as a nitrogen dopant for the adsorption of Acid red 18 (AR-18) dye from water. The doped biochars were also characterized for their performance during the treatment of synthetic effluents. The physicochemical characterization results showed that the N-doping process provoked remarkable chances on the biochar morphology, pore structure, and surface functionalities. N-doped biochar showed abundant nitrogen functional groups with 5.4 % of N in its structure while non-doped carbon showed traces with 0.47 %. Moreover, the specific surface area of doped biochar was dominated by mesopores (86.4 %) while non-doped was dominated by micropores (67.8 %). Raman analysis showed that the incorporation of N created more defects in the biochar structure. The adsorption experiments showed that the N-doping boosted the biochar adsorptive performance. The maximum adsorption capacity of the doped biochar was 545.2 mgg−1, while the non-doped exhibited 444.5 mgg−1, i.e., an increase of 22.6 %. The kinetic and equilibrium studies showed that Avrami fractional order and Liu models were the most suitable for describing the experimental AR-18 dye adsorption data. The equilibrium parameters were found to obey a nonlinear relationship with the temperature. Since the biochars are highly porous, pore filling was the main adsorption mechanism, however; AR-18 dye removal suggests that interactions such as electrostatic, hydrogen bonds, Lewis acid-base, and π-π between the adsorbent and the dye are involved. The thermodynamic studies showed that the removal of the AR-18 dye from the solution is dependent on temperature, exothermic, and spontaneous. The N-doped biochar showed excellent removal performances of contaminants from synthetic effluents confirming their high efficiency for color removal. This research shows that N-doping is an efficient strategy to design effective, low-cost, and sustainable adsorbents to remediate dye contamination in wastewater

Selective adsorption of gadolinium from real leachate using a natural bentonite clay

This article investigated the recovery of Gd3+ from real leachate of phosphogypsum (PG) using natural bentonite clay. Firstly, a detailed adsorption study was performed using synthetic Gd3+ solutions. Then, it was investigated the clay performance in the real PG leachate. The characterization results indicate classical bentonite characteristics, such as rugosity and an SBET 91.3 m² g−1, with meso (Dp =3.82 nm) and macroporous (Dp =52.6 nm). In addition, it was identified that the major functional groups are hydroxyl and silicate, with the presence of organic matter. The initial pH solution effect indicates that the optimum removal of Gd3+ is at pH (6), attributing to the pHpzc being at 5.75 and the negatively charged surface above the pHpzc. The Avrami fractional order model was the most suitable for describing the experimental kinetic data. The Langmuir was the proper model for describing the adsorption isotherms, indicating that the Gd3+ forms a monolayer at the surface of the bentonite. The maximum adsorption capacity at pH 6.0 was 121.5 mg g−1. The thermodynamic parameters indicate that the adsorption is spontaneous, with a standard enthalpy change of − 92.30 kJ mol−1, indicating an ionic exchange, where the Gd3+ tends to be organized at the surface, according to the standard entropy change of − 206.0 J K−1 mol−1. The fixed bed adsorption test showed that Gd3+ could be adsorbed for up to 200 min without regeneration. Regeneration results show that the citric acid is more efficient in desorbing the Gd3+ from the bentonite, reaching up to 8 cycles without efficiency loss. Finally, the bentonite clay could selectively recover Gd3+ from the real PG leachate

Selective adsorption of gadolinium from real leachate using a natural bentonite clay

This article investigated the recovery of Gd3+ from real leachate of phosphogypsum (PG) using natural bentonite clay. Firstly, a detailed adsorption study was performed using synthetic Gd3+ solutions. Then, it was investigated the clay performance in the real PG leachate. The characterization results indicate classical bentonite characteristics, such as rugosity and an SBET 91.3 m² g−1, with meso (Dp =3.82 nm) and macroporous (Dp =52.6 nm). In addition, it was identified that the major functional groups are hydroxyl and silicate, with the presence of organic matter. The initial pH solution effect indicates that the optimum removal of Gd3+ is at pH (6), attributing to the pHpzc being at 5.75 and the negatively charged surface above the pHpzc. The Avrami fractional order model was the most suitable for describing the experimental kinetic data. The Langmuir was the proper model for describing the adsorption isotherms, indicating that the Gd3+ forms a monolayer at the surface of the bentonite. The maximum adsorption capacity at pH 6.0 was 121.5 mg g−1. The thermodynamic parameters indicate that the adsorption is spontaneous, with a standard enthalpy change of − 92.30 kJ mol−1, indicating an ionic exchange, where the Gd3+ tends to be organized at the surface, according to the standard entropy change of − 206.0 J K−1 mol−1. The fixed bed adsorption test showed that Gd3+ could be adsorbed for up to 200 min without regeneration. Regeneration results show that the citric acid is more efficient in desorbing the Gd3+ from the bentonite, reaching up to 8 cycles without efficiency loss. Finally, the bentonite clay could selectively recover Gd3+ from the real PG leachate

Removal of captopril pharmaceutical from synthetic pharmaceutical-industry wastewaters: use of activated biochar derived from Butia catarinensis

A high surface area activated carbon was produced from the seed of Butia catarinensis (Bc), which was utilized for removing captopril from synthetic pharmaceutical industry wastewaters. The activated carbon was made by mixing ZnCl2 and Bc at a proportion of 1:1 and pyrolyzed at 600° (ABc-600). The material was characterized by the Boehm titration, hydrophilic/ hydrophobic ratio, elemental analysis, TGA, FTIR, and N2 isotherm (surface area (SBET), total pore volume (TPV), and pore size distribution (PSD)). The characterization data showed that the adsorbent displayed a hydrophilic surface due to the presence of several polar groups. The carbon material presented a TPV of 0.392 cm3 g−1, and SBET of 1267 m2 g−1. The equilibrium and kinetics data were suitably fitted to Liu isotherm and Avrami-fractional-order. The employment of the ABc-600 in the treatment of synthetic pharmaceutical industry wastewater exhibited high effectiveness in their removals (up to 99.0 %)